ZX Spectrum +2A/+3 support

ghidosoft · Mar 10, 2024 · 8c34e3f · 8c34e3f
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commit 8c34e3f
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Showing 11 changed files with 3,737 additions and 17 deletions.
diff --git a/README.md b/README.md
@@ -11,10 +11,9 @@ This is a cross-platform ZX Spectrum 48K/128K/+2 emulator written, for the fun o
 - Sound
 - Drag&drop file loading
 - Kempston joystick emulation (arrows and right-control for fire)
-- ZX 48K/128K/+2 spectrum
+- ZX 48K/128K/+2/+2A/+3 spectrum
 
 ## Roadmap
-- +2A/+3 spectrum
 - AY sound chip
 - .z80 snapshots
 - Fast loading

diff --git a/src/core/src/Emulator.hpp b/src/core/src/Emulator.hpp
@@ -35,7 +35,6 @@ namespace epoch
 
     struct EmulatorInfo
     {
-        std::string name;
         unsigned width;
         unsigned height;
         std::size_t frameClocks;

diff --git a/src/frontend/src/Application.cpp b/src/frontend/src/Application.cpp
@@ -100,7 +100,7 @@ namespace epoch::frontend
         assert(!m_window);
         const auto& emulatorInfo = m_emulator->info();
         m_window = std::make_unique<Window>(WindowInfo{
-            .title = "Epoch emulator: " + emulatorInfo.name,
+            .title = "Epoch emulator: " + m_currentEntry->name,
             .width = emulatorInfo.width * 2,
             .height = emulatorInfo.height * 2,
         });
@@ -350,7 +350,7 @@ namespace epoch::frontend
         m_emulator = entry.factory();
         m_currentEntry = &entry;
         m_settings->current().emulator.key = m_currentEntry->key;
-        m_window->setTitle("Epoch emulator: " + m_emulator->info().name);
+        m_window->setTitle("Epoch emulator: " + m_currentEntry->name);
     }
 
     void Application::setShader(const std::size_t index)

diff --git a/src/main.cpp b/src/main.cpp
@@ -37,6 +37,11 @@ int main()
                     .name = "ZX Spectrum 128K+2",
                     .factory = []() { return epoch::zxspectrum::ZXSpectrumEmulator::create128KPlus2(); },
                 },
+                {
+                    .key = "ZXSpectrum128K+3",
+                    .name = "ZX Spectrum 128K+2A/+3",
+                    .factory = []() { return epoch::zxspectrum::ZXSpectrumEmulator::create128KPlus3(); },
+                },
             },
     };
     epoch::frontend::Application application{configuration};

diff --git a/src/zxspectrum/CMakeLists.txt b/src/zxspectrum/CMakeLists.txt
@@ -16,6 +16,7 @@ add_library(epoch_zxspectrum
     "src/roms/Rom48K.cpp"
     "src/roms/Rom128K.cpp"
     "src/roms/Rom128K+2.cpp"
+    "src/roms/Rom128K+3.cpp"
     "src/roms/RomZXTest.cpp"
 )
 

diff --git a/src/zxspectrum/src/Roms.hpp b/src/zxspectrum/src/Roms.hpp
@@ -35,6 +35,9 @@ namespace epoch::zxspectrum::roms
     // 128K+2 rom downloaded from https://mdfs.net/Software/Spectrum/ROMImages/128k+2.rom
     extern const uint8_t Rom128KPlus2[32 * 1024];
 
+    // 128K+3 rom downloaded from https://mdfs.net/Software/Spectrum/ROMImages/128k+3.rom
+    extern const uint8_t Rom128KPlus3[64 * 1024];
+
     extern const uint8_t RomZXTest[8 * 1024];
 }  // namespace epoch::zxspectrum::roms
 

diff --git a/src/zxspectrum/src/Ula.cpp b/src/zxspectrum/src/Ula.cpp
@@ -18,6 +18,7 @@
 
 #include <cassert>
 #include <cstring>
+#include <stdexcept>
 
 namespace epoch::zxspectrum
 {
@@ -65,6 +66,7 @@ namespace epoch::zxspectrum
         m_vramSelect = 5;
         m_romSelect = 0;
         m_pagingState = 0;
+        m_pagingPlus3 = 0;
 
         m_frameCounter = 0;
         m_x = -HorizontalRetrace;
@@ -143,6 +145,8 @@ namespace epoch::zxspectrum
                     return m_pagingState;
                 }
                 break;
+            case UlaType::zx128kplus3:
+                break;
         }
         return 0xff;
     }
@@ -177,6 +181,43 @@ namespace epoch::zxspectrum
                     }
                 }
                 break;
+            case UlaType::zx128kplus3:
+            {
+                bool shouldUpdate = false;
+                if ((port & 0b1100000000000010) == 0b0100000000000000)
+                {
+                    if ((m_pagingState & 0b00100000) == 0)
+                    {
+                        m_pagingState = value;
+                        shouldUpdate = true;
+                    }
+                }
+                else if ((port & 0b1111000000000010) == 0b0001000000000000)
+                {
+                    if ((m_pagingState & 0b00100000) == 0)
+                    {
+                        m_pagingPlus3 = value;
+                        shouldUpdate = true;
+                    }
+                }
+                if (shouldUpdate)
+                {
+                    if (m_pagingPlus3 & 0x01)
+                    {
+                        // Special paging mode
+                        const auto modeSelect = (m_pagingPlus3 >> 1) & 0x03;
+                        throw std::runtime_error("Paging special mode not yet implemented");
+                    }
+                    else
+                    {
+                        // Normal paging mode
+                        m_ramSelect = m_pagingState & 0x07;
+                        m_vramSelect = (m_pagingState & 0b00001000) ? 7 : 5;
+                        m_romSelect = ((m_pagingPlus3 >> 1) & 0x02) | ((m_pagingState >> 4) & 0x01);
+                    }
+                }
+                break;
+            }
         }
     }
 

diff --git a/src/zxspectrum/src/Ula.hpp b/src/zxspectrum/src/Ula.hpp
@@ -29,7 +29,8 @@ namespace epoch::zxspectrum
     enum class UlaType
     {
         zx48k,
-        zx128k
+        zx128k,
+        zx128kplus3,
     };
 
     class Ula final : public Z80Interface
@@ -75,13 +76,14 @@ namespace epoch::zxspectrum
     private:
         UlaType m_type;
 
-        std::array<MemoryBank, 2> m_rom{};
+        std::array<MemoryBank, 4> m_rom{};
         std::array<MemoryBank, 8> m_ram{};
 
         uint8_t m_ramSelect{0};
         uint8_t m_vramSelect{5};
         uint8_t m_romSelect{0};
         uint8_t m_pagingState{};
+        uint8_t m_pagingPlus3{};
 
         uint8_t m_floatingBusValue{};
         uint8_t m_border{};

diff --git a/src/zxspectrum/src/ZXSpectrumEmulator.cpp b/src/zxspectrum/src/ZXSpectrumEmulator.cpp
@@ -46,9 +46,8 @@ namespace epoch::zxspectrum
     };
     const Palette ZXSpectrumEmulator::DefaultPalette{defaultColors};
 
-    ZXSpectrumEmulator::ZXSpectrumEmulator(std::string name, std::unique_ptr<Ula> ula)
-        : Emulator{{std::move(name),
-                    Width,
+    ZXSpectrumEmulator::ZXSpectrumEmulator(std::unique_ptr<Ula> ula)
+        : Emulator{{Width,
                     Height,
                     TStatesPerFrame,
                     FramesPerSecond,
@@ -66,20 +65,22 @@ namespace epoch::zxspectrum
 
     std::unique_ptr<ZXSpectrumEmulator> ZXSpectrumEmulator::create48K()
     {
-        return std::make_unique<ZXSpectrumEmulator>("ZX Spectrum 48K",
-                                                    std::make_unique<Ula>(UlaType::zx48k, roms::Rom48K));
+        return std::make_unique<ZXSpectrumEmulator>(std::make_unique<Ula>(UlaType::zx48k, roms::Rom48K));
     }
 
     std::unique_ptr<ZXSpectrumEmulator> ZXSpectrumEmulator::create128K()
     {
-        return std::make_unique<ZXSpectrumEmulator>("ZX Spectrum 128K",
-                                                    std::make_unique<Ula>(UlaType::zx128k, roms::Rom128K));
+        return std::make_unique<ZXSpectrumEmulator>(std::make_unique<Ula>(UlaType::zx128k, roms::Rom128K));
     }
 
     std::unique_ptr<ZXSpectrumEmulator> ZXSpectrumEmulator::create128KPlus2()
     {
-        return std::make_unique<ZXSpectrumEmulator>("ZX Spectrum 128K+2",
-                                                    std::make_unique<Ula>(UlaType::zx128k, roms::Rom128KPlus2));
+        return std::make_unique<ZXSpectrumEmulator>(std::make_unique<Ula>(UlaType::zx128k, roms::Rom128KPlus2));
+    }
+
+    std::unique_ptr<ZXSpectrumEmulator> ZXSpectrumEmulator::create128KPlus3()
+    {
+        return std::make_unique<ZXSpectrumEmulator>(std::make_unique<Ula>(UlaType::zx128kplus3, roms::Rom128KPlus3));
     }
 
     void ZXSpectrumEmulator::reset()

diff --git a/src/zxspectrum/src/ZXSpectrumEmulator.hpp b/src/zxspectrum/src/ZXSpectrumEmulator.hpp
@@ -36,13 +36,14 @@ namespace epoch::zxspectrum
         static const Palette DefaultPalette;
 
     public:
-        ZXSpectrumEmulator(std::string name, std::unique_ptr<Ula> ula);
+        explicit ZXSpectrumEmulator(std::unique_ptr<Ula> ula);
         ~ZXSpectrumEmulator() override;
 
     public:
         static std::unique_ptr<ZXSpectrumEmulator> create48K();
         static std::unique_ptr<ZXSpectrumEmulator> create128K();
         static std::unique_ptr<ZXSpectrumEmulator> create128KPlus2();
+        static std::unique_ptr<ZXSpectrumEmulator> create128KPlus3();
 
     public:
         ZXSpectrumEmulator(const ZXSpectrumEmulator& other) = delete;